Internal combustion engine



Jan. 26, 1932. P. E. MACK INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 Filed June 4, 1931 IN VE N 7' 0/? Ferry .5. Maa/c A TTORNE V Jan. 26 1932.. P. E. MACK 1,842,530

INTERNAL COMBUSTION ENGINE Filed June 4. 1931 2 Sheets-Sheet 2 INVENTOR Ferry E 'M-ya/r ATTORNEY Patented Jan. 26, 1932 UNITED STATES PATENT OFFICE PERRY E. HACK, OI MILWAUKEE, WISCONSIN, ASSIGNOR TO BRIGGS &: STRATTON COR- PORA'I'ION, OF MILWAUKEE, WISCONSIN, A CORIORATION OF DELAWARE INTERNAL COMBUSTION ENGINE Application filed June 4,

This invention relates to certain new and useful improvements in internal combustion engines, and refers more particularly to the crank shaft bearings therefore, and the means for lubricating the hearings.

in single cylinder internal combustion en gines, the pressure pulsations withln the crank case due to the movement of the piston produces jets of air through the clearance space of the bearings which forces the 011 put of the crank case. This obviously is ob ectionable, for not only does it exhaust the oil supply prematurely, but often causes damage to surrounding mechanism such as the fly wheel magneto, and the like.

An attempt has been made to overcome this objectionable feature, by providing an annular groove at the outer end of each bearing and a channel to return the oil from the groove to the crank case. This expedient however, is ineffective on single cylinder engines; and it is therefore, an object of this invention to provide means whereby this manner of preventing the oil from being forced out of the hearing may be effectively employed with a single cylinder combustion enne. lt more specific object of this invention residesin the provision of valve means associated with the return channel or passage which is operated by pulsations of pressure within the crank case to open the channel onlv when a suction is established by the up' strdke of the piston.

And afurther ob'ect of this invention is to provide a simple and effective mounting til tit)

1931 Serial in. 542,090.

plete example of the physical embodiment of this invention is illustrated, constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side view of a single cylinder combustion engine with parts broken away and in section and illustrating the application of this invention thereto;

Figure is a cross section view taken glgough Figure 1 on the plane of the line Figure 3 is 'an enlarged detail view illustratlng the construction of the valve mountmg; and v Figure 4 is a detail section view taken flrzugh Figure 2 on the plane of the line internal combustion engine having a cylinder 6 in which a piston, not shown, is mounted to drive a crank shaft 7 through the medium of a connectin rod 8. The crank shaft 7 is 1ournalled in earings carried by the crank case and in the present instance but one hearing 9 is shown. Outwardly of the bearing 9, the shaft 7 mounts a fly wheel 10.

As is customary the crankcase is adapted to be filled with oil or other lubricant which is conducted to the bearing 9, to enter the clearance between its bore and the shaft through an oil inlet port 11 at the inner end of the bearing.

As hereinbefore noted, the plenum established within the crank case by the down stroke of the piston tends to force the oil out of the bearing, and to preclude the oil fromleaving the bearing, an annular groove 12 is formed in the outer end of the bearing in communication with its bore. This groove communicates with a return passage or duct 13, at its bottom, which duct extends diagonally downwardly to'return the oil from the outer end of the bearing to the crank case.

' This construction alone, however, does not function properly'in a single cylinder type of internal combustion engine, in that the alternate pulsations of pressure and partial vacuum within the crank case prevent the oil from flowing down the return duct. To overcome this objectionable feature and to enable the oil to be properly returned from the collector groove 12, a novel valve structure indicated generally by the numeral 14 is provided at the lower or outlet end of the return duct 13.

This valve structure 14. as best shown in Figures 3 and 4 comprises a mounting member 15 provided with a central bore 16 and diametrically extended arms 17. Screws 18 passed-through openings in the outer ends of the arms 17 and threaded into suitable openings in the adjacent portion of the crank case inner wall 19 serve to hold the mounting member 15 in position with its bore 16 aligned with the adjacent end of the-return duct 13. A packing member or gasket 20 is preferably placed between the adjacent faces of the mounting member 15 and the crank case wall 19 to prevent leakage.

The mounting member 15 is counterbored as at 21 and the bottom of the eounterbore provides an annular valve seat 22 surrounding the bore 16. A light metal disc 23 positioned in the counterbore 21 forms a flap valve which is adapted to engage the seat 22 and close off communication between the return duct 13 and the interior of the crank case. The valve is held from displacement by a cross bar 24 extending diametrically across the bore and having its ends provided with apertures through which the attaching screws 18 pass, the space between the cross bar 24 and the valve seat 23 being sufiicient to permit the valve disc to move to and from a closed position. v

The operation of the device is obvious, for during the upstroke of the cylinder when a partial vacuum exists within the crank case, the valve 23 will be drawn away from the seat 22 to permit the oil within the collector groove 12 to be drawn into the crank case through. the return duct 13, andduring the down stroke of the piston the increased pressure within the crank case closes the valve 23 and prevents this pressure within the crank case from blowing the oil back up into the collector groove and out of the end of the bearing.

While the drawings show but one bearing, and an application to an internal combustion engine, any number of hearings in an internal combustionengine or any other similar machine or apparatus in which similar pressure conditions are encountered, may be equipped with valved means for preventing loss of. oil therethrough, without deviating from the spirit of the invention.

lVhat I claim as my invention is:

1. In an internal combustion engine including a crank case, a shaft, and a bearing for the shaft carried by one wall of the crank case, means for preventing lubricant from being forced through the bearing including means for returning lubricant from the outer portion of the bearing to the crank case, and a valve operable by pressure within the crank case to close off communication between said communicating means and the interior of the crank case.

2. In combination with an internal combustion engine having a crank case, a crank shaft, a bearing for the shaft adapted to receive oil from the crank case and a piston, reciprocation of the piston producing pressure pulsations within the crank case, means for preventing said pressure pulsations from forcing lubricant out of the bearing including a communication between the bearing outer end portion and the crank case for returning lubricant from the bearing to the crank case, and a valve operable by the pressure pulsations within the crank case to open only during the upstroke of the piston.

3. In combination with an internal combustion engine having a crank case adapted to contain lubricant, a shaft, a bearing for the shaft communicating with the interior of the crank case and adapted to receive lubricant therefrom and a piston which in its up and down strokes produces respectively, a partial vacuum and a plenum Within the crank case, means for preventing oil conducted from the crank case to the bearing from being forced out through the bearing by the plenum within the crank case including means for returning the lubricant from the outer end of the bearing to the crank case, a valve, and means for mounting the valve for movement to and from a position closing off communication between said communicating means and the interior of the crank case and whereby the valve is free to be moved by the alternate changes of pressure within the crank case produced by the piston.

4. In combination with the crank "case of an internal combustion engine in which pressure pulsations are produced by the piston of the engine, a shaft, a bearing for the shaft communicating with the interior of the crank case, said bearing being supplied with a lubricant from the crank case and having a lubricant collector groove in its outer end portion and a lubricant return duct communicating the collector groove with the interior of the crank case, and a valve for closing off communication between said return duct and the interior of the crank case and adapted to be closed by pressure withi the crank case.

5. In combination-with the crank case of an internal combustion engine in which pressure pulsations are produced by the piston on the engine, a shaft, a bearing for the shaft communicating with the interior of the crank case, said bearing being supplied with lubricant from the crank case 'and having a lubricant collector roove in its outer end portion and a lubricant return duct communicating the collector groove with the interior of the crank case, a flap valve, and means mounting the flap valve within the crank case to close off communication between the return duct and the interior of the crank case by pressure within the crank case and to be opened by a partial vacuum within the crank case to draw lubricant through the return ductfrom the collector groove.

6. In combination with the crank case of 15 an internal combustion engine having a piston and adapted to contain lubricant, a shaft, a bearing for the shaft carried by one wall of the crank case whereby the clearance between the bearing bore and the shaft is in communication with the interior of the crank case. said shaft being adapted to receive lubricant from the crank case; and means for preventing pressure within the crank case produced by the downstroke of the piston E5 from forcing the lubricant out of the bearing and comprising means for returning the lubricant from the outer end portion of the bearing to the crank case, and a valve for controlling communication between the return means and the interior of the crank case and operable to close ofi communication between the return means and the interior of the crank case by the pressure pulsations withi the crank case.

7. In combination with a substantially closed chamber adapted to contain a lubricant and subject to pressure pulsations, a bearing communicating with the interior of the chamber, a shaft in the bearing, said bearing being supplied with lubricant from the chamber. and means for preventing the pressure within the chamber from forcing the lubricant out through the bearing including means for conducting the lubricant from the outer end portion of the bearing to the cham- I her, and avalve closed by pressure within the chamber for closing of! communication between saicl conducting means and the chem be]: interior.

50 In testimony whereof I have hereunto affixecl my signature. PERRY E, MACK. 

